One of the main objects of the aromatization of foodstuffs for instance is to restore the original quality and nature of the flavour, aroma and taste of a given foodstuff material. Very often in fact the organoleptic properties of foodstuffs particularly diminish or are somehow modified in the course of the processes of freezing and storage, or during the modifications, such as cooking or baking, to which the foodstuffs are subjected in order to yield an edible material.
In the past the aromatization was mainly achieved by using materials of natural origin. Nowadays, however, synthetic chemical compounds are used at an ever increasing rate. Said compounds possess the advantage of being available very often in unlimited quantities and at prices lower than those of the natural materials. Moreover, due to the fact that the flavouring character of a natural material is the result of the overall effect determined by the combination and interaction of each of its constituents, the effects achieved by said natural material are very often not as well reproducible as those obtained by the use of the pure synthetic compounds.
In the field of perfumery the man in the art has to solve a similar problem in attempting to reconstitute the olfactive notes of certain natural essential oils or extracts. The perfumer's creativity however is continually boosted by the finding of new synthetic compounds, the organoleptic properties of which will enable him to introduce unprecedented olfactive characters or nuances into new phantasy perfume compositions.
As a consequence, the problem that the chemical industry has to solve is to satisfy the increasing demand of organoleptically interesting chemicals in order to better suit the specific needs of flavourists and perfumers.
The compounds of formula I wherein one of the pairs of symbols R.sup.1 and R.sup.2 and R.sup.3 and R.sup.4, respectively, represents a methyl group and the other is a hydrogen atom possess a sesquiterpenoid skeleton containing 12 carbon atoms. Hitherto the use of these specific compounds as perfuming and/or flavouring ingredients has never been recognized in the art.
By means of an original, industrially and economically advantageous process of synthesis is now possible to put to the disposal of perfumers and flavourists a new class of valuable perfuming and flavouring ingredients.